How Far Is It to the Center of the Earth?
If you could drill a hole to the center of the Earth, you would find it measured about 3,958 miles (6,371 kilometers). The figure is approximate because the Earth is not a perfectly round globe. It bulges slightly at the equator.
The surface of the Earth is usually cool beneath our feet. But deep inside the Earth, it is very hot. At two miles below the surface, the temperature is high enough to boil water. The very center of the Earth is believed to be a solid core of iron and nickel, surrounded by molten iron, at a temperature of 10,000 F.
In truth, we have almost no direct knowledge of anything beneath the crust — all of our data is inferred from the seismic waves of earthquakes bouncing off the various layers, and from various bits of the Earth’s interior that bubble up to the surface, such as volcanic magma.
While we would love to dig down to the core and take some exact measurements, it simply isn’t possible with our current drilling technology — and probably never will be. The deepest we have ever drilled is the Kola Superdeep Borehole, which is just 12km deep.